Sengoku Gensokyo (戦国幻想郷)

Hakurei shrine, in Gensoukyou.
The shrine maiden Reimu Hakurei and her friend Marisa Kirisame
enjoy passing their usual time which is lack of happenings.

…… However, the tranquility is broken by the yokai of boundary, Yukari Yakumo.
She offers a new way of duel substituting for the conventional spell card rule.
Reimu gets unwillingly involved in it while Marisa welcomes the situation.
Later other Gensoukyou residents join the battle one by one.

The happening starts growing and involving even more things.
A decisive battle begins in Gensoukyou!